A sample of 12 614 star-forming galaxies ( SFGs ) with stellar mass > 10 ^ { 9.5 } M _ { \odot } between 0.6 < z < 0.8 from COSMOS is selected to study the intrinsic scatter of the correlation between star formation rate ( SFR ) and stellar mass .
We derive SFR from ultraviolet ( UV ) and infrared ( IR ) luminosities .
A stacking technique is adopted to measure IR emission for galaxies undetected at 24 \micron .
We confirm that the slope of the mass-SFR relation is close to unity .
We examine the distributions of specific SFRs ( SSFRs ) in four equally spaced mass bins from 10 ^ { 9.5 } M _ { \odot } to 10 ^ { 11.5 } M _ { \odot } .
Different models are used to constrain the scatter of SSFR for lower mass galaxies that are mostly undetected at 24 \micron .
The SFR scatter is dominated by the scatter of UV luminosity and gradually that of IR luminosity at increasing stellar mass .
We derive SSFR dispersions of 0.18 , 0.21 , 0.26 and 0.31 dex with a typical measurement uncertainty of \lesssim 0.01 dex for the four mass bins .
Interestingly , the scatter of the mass-SFR relation seems not constant in the sense that the scatter in SSFR is smaller for SFGs of stellar mass < 10 ^ { 10.5 } M _ { \odot } .
If confirmed , this suggests that the physical processes governing star formation become systematically less violent for less massive galaxies .
The SSFR distribution for SFGs with intermediate mass 10 ^ { 10 } -10 ^ { 10.5 } M _ { \odot } is characterized by a prominent excess of intense starbursts in comparison with other mass bins .
We argue that this feature reflects that both violent ( e.g. , major/minor mergers ) and quiescent processes are important in regulating star formation in this intermediate mass regime .